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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: pfilt.h,v 1.4 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * Finding and testing prime numbers |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
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30 | #ifndef CATACOMB_PFILT_H |
31 | #define CATACOMB_PFILT_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #ifndef CATACOMB_MP_H |
40 | # include "mp.h" |
41 | #endif |
42 | |
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43 | #ifndef CATACOMB_PRIMETAB_H |
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44 | # include "primetab.h" |
45 | #endif |
46 | |
47 | /*----- Data structures ---------------------------------------------------*/ |
48 | |
49 | typedef struct pfilt { |
50 | mp *m; |
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51 | smallprime r[NPRIME]; |
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52 | } pfilt; |
53 | |
54 | /*----- Functions provided ------------------------------------------------*/ |
55 | |
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56 | /* --- @pfilt_smallfactor@ --- * |
57 | * |
58 | * Arguments: @mp *m@ = integer to test |
59 | * |
60 | * Returns: One of the @PGEN@ result codes. |
61 | * |
62 | * Use: Tests a number by dividing by a number of small primes. This |
63 | * is a useful first step if you're testing random primes; for |
64 | * sequential searches, @pfilt_create@ works better. |
65 | */ |
66 | |
67 | extern int pfilt_smallfactor(mp */*m*/); |
68 | |
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69 | /* --- @pfilt_create@ --- * |
70 | * |
71 | * Arguments: @pfilt *p@ = pointer to prime filtering context |
72 | * @mp *m@ = pointer to initial number to test |
73 | * |
74 | * Returns: A @PGEN@ result code. |
75 | * |
76 | * Use: Tests an initial number for primality by computing its |
77 | * residue modulo various small prime numbers. This is fairly |
78 | * quick, but not particularly certain. If a @PGEN_TRY@ |
79 | * result is returned, perform Rabin-Miller tests to confirm. |
80 | */ |
81 | |
82 | extern int pfilt_create(pfilt */*p*/, mp */*m*/); |
83 | |
84 | /* --- @pfilt_destroy@ --- * |
85 | * |
86 | * Arguments: @pfilt *p@ = pointer to prime filtering context |
87 | * |
88 | * Returns: --- |
89 | * |
90 | * Use: Discards a context and all the resources it holds. |
91 | */ |
92 | |
93 | extern void pfilt_destroy(pfilt */*p*/); |
94 | |
95 | /* --- @pfilt_step@ --- * |
96 | * |
97 | * Arguments: @pfilt *p@ = pointer to prime filtering context |
98 | * @mpw step@ = how much to step the number |
99 | * |
100 | * Returns: One of the @PGEN@ result codes. |
101 | * |
102 | * Use: Steps a number by a small amount. Stepping is much faster |
103 | * than initializing with a new number. The test performed is |
104 | * the same simple one used by @primetab_create@, so @PGEN_TRY@ |
105 | * results should be followed up by a Rabin-Miller test. |
106 | */ |
107 | |
108 | extern int pfilt_step(pfilt */*p*/, mpw /*step*/); |
109 | |
110 | /* --- @pfilt_muladd@ --- * |
111 | * |
112 | * Arguments: @pfilt *p@ = destination prime filtering context |
113 | * @const pfilt *q@ = source prime filtering context |
114 | * @mpw m@ = number to multiply by |
115 | * @mpw a@ = number to add |
116 | * |
117 | * Returns: One of the @PGEN@ result codes. |
118 | * |
119 | * Use: Multiplies the number in a prime filtering context by a |
120 | * small value and then adds a small value. The destination |
121 | * should either be uninitialized or the same as the source. |
122 | * |
123 | * Common things to do include multiplying by 2 and adding 0 to |
124 | * turn a prime into a jump for finding other primes with @q@ as |
125 | * a factor of @p - 1@, or multiplying by 2 and adding 1. |
126 | */ |
127 | |
128 | extern int pfilt_muladd(pfilt */*p*/, const pfilt */*q*/, |
129 | mpw /*m*/, mpw /*a*/); |
130 | |
131 | /* --- @pfilt_jump@ --- * |
132 | * |
133 | * Arguments: @pfilt *p@ = pointer to prime filtering context |
134 | * @const pfilt *j@ = pointer to another filtering context |
135 | * |
136 | * Returns: One of the @PGEN@ result codes. |
137 | * |
138 | * Use: Steps a number by a large amount. Even so, jumping is much |
139 | * faster than initializing a new number. The test peformed is |
140 | * the same simple one used by @primetab_create@, so @PGEN_TRY@ |
141 | * results should be followed up by a Rabin-Miller test. |
142 | * |
143 | * Note that the number stored in the @j@ context is probably |
144 | * better off being even than prime. The important thing is |
145 | * that all of the residues for the number have already been |
146 | * computed. |
147 | */ |
148 | |
149 | extern int pfilt_jump(pfilt */*p*/, const pfilt */*j*/); |
150 | |
151 | /*----- That's all, folks -------------------------------------------------*/ |
152 | |
153 | #ifdef __cplusplus |
154 | } |
155 | #endif |
156 | |
157 | #endif |